The main objective of this work was to study the effect of plastic deformation (cold
work) and heat treatment on the hydrogen permeation of a seamless carbon steel pipe,
commonly used in the oil industry, considering the relationship between microstructure and
hydrogen diffusion. The steel samples were characterized, by scanning and transmission
electron microscopies to establish the relationship between microstructure and defects on
the hydrogen damage.
The hydrogen permeation tests were performed on samples of the above mentioned
steel in the different conditions. The experiments were carried out following the Devanathan
and Stachurski technique, using 0.1M Na2SO4 as the electrolyte in the cathodic
compartment and 0.1 M NaOH as the electrolyte in the anodic one. The obtained results
showed that the hydrogen absorption capacity is higher when the steel has the larger
deformation degree. This could be associated to the presence of substructures with small
cell size range (0.01-0.15 µm), meaning a higher dislocation density, which could act as a
preferential site for a greater hydrogen absorption and transportation. On the other hand,
with increasing deformation, the mean hydrogen flux is greater than measured through
steel in the as received condition.
Keywords: Steel, hydrogen damage, hydrogen permeation, cold work.